Micromechanical devices are small structures typically fabricated on a semiconductor wafer using techniques such as optical lithography, doping, metal sputtering, oxide deposition, and plasma etching which have been developed for the fabrication of integrated circuits. Micromirror devices are a type of micromechanical device. Other types of micromechanical devices include accelerometers, pressure and flow sensors, gears and motors. While some micromechanical devices, such as pressure sensors, flow sensors, and micromirrors have found commercial success, other types have not yet been commercially viable.
Micromirror devices are primarily used in optical display systems. In display systems, the micromirror is a light modulator that uses digital image data to modulate a beam of light by selectively reflecting portions of the beam of light to a display screen. While analog modes of operation are possible, micromirrors typically operate in a digital bistable mode of operation and as such are the core of the first true digital full-color image projection systems.
Micromirrors, and other contacting types of micromechanical systems, typically require some sort of lubrication system to prevent static friction, often referred to as stiction, from preventing proper operation of the device. Micromechanical systems also typically require a getter to collect water vapor and other contaminants that enter the package. The water vapor can attach to the surface of the device and result in van der Waals forces which prevent movement of the micromechanical device. Care must be exercised in the manufacture of getters to prevent the getters from introducing contaminants into the micromechanical device package.
Methods of quickly producing clean getters are needed to support volume production of micromechanical systems.